Myofascial pain (MFP) is the most common disorder causing chronic pain in the head and neck and is characterized by taut bands of muscle containing hyperirritable areas known as trigger points (TP). TP's appear to be activated by chronic mechanical strain, trauma, or overload to the muscle and the associated tenderness and slight diminished range of motion are the most common objective characteristics. Exercise has been the most common treatment proposed to reduce subjective pain complaints of MFP. Although the mechanism of exercise is unclear, numerous authors suggest that they relax the taut muscle bands that are characteristic of MFP, increase range of motion and muscle length, and thereby reduce the mechanical strain in normal functional movements. Although range of motion or stretching exercises appear to be a cornerstone of treatment for MFP, there have been no controlled studies documenting their single effects on symptom severity, jaw range of motion, or muscle tenderness. One reason the mechanisms and the efficacy of exercise remain unclear is because studies involving MFP suffer from methodological problems such as the lack of criteria defining MFP, lack of standardized diagnostic and treatment protocols, and lack of objective measures of severity. The aim of this study is to used improved methodological techniques to compare the effects of a short-term program (4 weeks) of range of motion exercises as compared to a placebo medication control group on increasing range of motion while reducing jaw pain and tenderness in a group of 50 masticatory myofascial pain patients. A double blinded random controlled study with a placebo medication control group is proposed. Outcome measures that have been previously tested or reliability and validity will be used and include interincisal range of motion, symptom severity index, weekly pain ratings, pressure pain thresholds of the masseter and temporalis muscles using index, weekly pain ratings, pressure pain thresholds of the masseter and temporalis muscles using PAMP, and the scope of muscle tenderness using the MI. As a results of this study, treatment regimens may be better understood to provide the most effective intervention in the treatment of MPS. The data collected in this study will also be baseline information for studies investigating the long-term stability of short-term treatment outcomes.